Identification document with dynamic window

ABSTRACT

An identification document including a multilayer laminate having a core layer defining an opening therethrough, and a dynamic window in the opening. The dynamic window includes an optically variable coating on at least a front or a back of the dynamic window. The optically variable coating appears transparent when viewed from the front of the identification document in light transmitted through the dynamic window from the back of the identification document toward the front of the identification document, and appears nontransparent when viewed from the front of the identification document in light reflected from the front of the identification document. Fabricating an identification document with a dynamic window includes forming an opening in a core layer, positioning a dynamic window in the opening, and plate laminating the core layer and the dynamic window between at least one outer layer on each side of the core layer.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Patent Application Ser. No.62/098,276 entitled “IDENTIFICATION DOCUMENT WITH WINDOW” and filed onDec. 30, 2014; U.S. Patent Application Ser. No. 62/098,236 entitled“IDENTIFICATION DOCUMENT WITH MULTIVIEW IMAGE” and filed on Dec. 30,2014; and U.S. Patent Application Ser. No. 62/098,904 entitled“IDENTIFICATION DOCUMENT WITH EMBEDDED 3D INFORMATION” and filed on Dec.31, 2014, all of which are herein incorporated by reference in theirentirety.

TECHNICAL FIELD

This disclosure generally relates to a laminated identification (“ID”)document including a dynamic window.

BACKGROUND

Identification (“ID”) documents play a critical role in today's society.One example of an ID document is an ID card. ID documents are used on adaily basis to prove identity, to verify age, to access a secure area,to evidence driving privileges, to cash a check, and so on. Airplanepassengers are required to show an ID document during check in, securityscreening, and prior to boarding their flight. In addition, because welive in an ever-evolving cashless society, ID documents are used to makepayments, access an automated teller machine (ATM), debit an account,make a payment, and the like.

Many ID documents include a core layer which can be pre-printed, such asa light-colored, opaque material. The core is laminated with atransparent material to form a so-called “card blank.” Information, suchas variable personal information (e.g., photographic information), isprinted on the card blank. The information may include an indicium orindicia, such as the invariable information common to a large number ofID documents (e.g., for example the name and logo of the organizationissuing the documents). To protect the information that is printed, anadditional layer of transparent overlaminate is typically coupled to thecard blank and printed information.

Many ID documents are made via roll laminating processes. Rolllaminating processes introduce stresses by stretching and laminating ina non-uniform manner, resulting in steady state processes that producethermal stresses that change over time. These ID documents typicallyrequire adhesives, the presence of which may promote tampering that canresult in separation of these ID documents into layers.

SUMMARY

In a first general aspect, an identification document includes amultilayer laminate having a core layer defining an openingtherethrough, and a dynamic window in the opening. The dynamic windowincludes an optically variable coating on at least a front or a back ofthe dynamic window. The front of the dynamic window is between a frontof the identification document and the back of the dynamic window, andthe back of the dynamic window is between a back of the identificationdocument and the front of the dynamic window. The optically variablecoating appears to be transparent when viewed from the front of theidentification document in light transmitted through the dynamic windowfrom the back of the identification document toward the front of theidentification document, and appears to be nontransparent when viewedfrom the front of the identification document in light reflected fromthe front of the identification document.

In a second general aspect, fabricating an identification documentincludes forming an opening in a core layer, positioning a dynamicwindow in the opening, and plate laminating the core layer and thedynamic window between at least one outer layer on each side of the corelayer. The dynamic window includes an optically variable coating on atleast a front or a back of the dynamic window. The front of the dynamicwindow is between a front of the identification document and the back ofthe dynamic window, and the back of the dynamic window is between a backof the identification document and the front of the dynamic window. Theoptically variable coating appears to be transparent when viewed from afront of the identification document in light transmitted through thedynamic window from a back of the identification document toward thefront of the identification document, and appears to be nontransparentwhen viewed from the front of the identification document in lightreflected from the front of the identification document.

Implementations of the first or second general aspect may include one ormore of the following features.

The dynamic window typically includes a clear plastic layer, and theoptically variable coating is on a front of the clear plastic layer, aback of the clear plastic layer, or both, with the front of the clearplastic layer corresponding to the front of the dynamic window, and theback of the clear plastic layer corresponding to the back of the dynamicwindow. The optically variable coating may include an inorganic pigmentdispersed in a binder, with the inorganic pigment including particlesaligned in the binder to yield a mirror effect in reflected light. Theoptical intensity of the dynamic window changes according to the angleat which it is viewed in reflected light. For example, a maximum opticalintensity of the dynamic window in reflected light is achieved near theangle at which the incident light is totally reflected from theoptically variable coating, and the dynamic window appears to be opaquewhen the incident light is totally reflected from the optically variablecoating.

In some cases, the identification document includes an image on a layerof the multilayer laminate between a front of the identificationdocument and the front of the dynamic window or between a back of theidentification document and the back of the dynamic window, with theimage superimposed on the dynamic window. The image may be a colorimage. When the optically variable coating is on a back of the dynamicwindow and the image is on a layer of the multilayer laminate betweenthe front of the identification document and the front of the dynamicwindow, the image is visible from the front of the identificationdocument in light reflected from the front of the identificationdocument and is visible from the front of the identification document inlight transmitted from the back of the identification document throughthe dynamic window. When the optically variable coating is on a back ofthe dynamic window and the image is on a layer of the multilayerlaminate between the front of the identification document and the frontof the dynamic window, the image is invisible from the back of theidentification document in light reflected from the back of theidentification document and is visible from the back of theidentification document in light transmitted from the front of theidentification document through the dynamic window.

In certain cases, the dynamic window is laser engraved such that thelaser engraving is visible when the identification document is viewedfrom the front with light transmitted from the back of theidentification document to the front of the identification documentthrough the dynamic window, and is not visible when the identificationdocument is viewed from the front of the identification document inreflected light.

The identification document typically includes a tie layer laminated toeach side of the core layer. A laser engraved image (e.g., a hologram ora KINEGRAM) may be formed in at least one of the tie layers. The laserengraved image may be formed such that the optically variable coating onthe dynamic window is not altered (e.g., is not ablated or removed) bythe engraving process. A structural layer is typically laminated to theouter side of each tie layer, and a receiver layer is typically adjacentthe outer side of each structural layer. The multilayer laminate may bedevoid of an adhesive composition. That is, the laminating process mayoccur in the absence of an adhesive composition.

In some cases, identical images are printed on each receiver layer andon the front or back of the dynamic window or superimposed over thefront or back of the dynamic window, wherein the identical images aresuperimposed such that the identical images appear to be a single imageor three separate images based on the angle at which the dynamic windowis viewed from the front of the identification document in lighttransmitted through the dynamic window from a back of the identificationdocument toward the front of the identification document.

In certain cases, the optically variable coating is a first opticallyvariable coating on the front of the dynamic window, and theidentification document includes a second optically variable coating onthe back of the dynamic window. The first optically variable coating maybe the same as or different from the second optically variable coating.The optically variable coating may completely cover the front of thedynamic window, the back of the dynamic window, or both. The opticallyvariable coating may cover selected portions of the front of the dynamicwindow, the back of the dynamic window, or both.

The details of one or more implementations of the subject matterdescribed in this specification are set forth in the accompanyingdrawings and the description below. Other features, aspects, andadvantages of the subject matter will become apparent from thedescription, the drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts an ID document with a dynamic window viewed from thefront of the ID document in reflected light having a first angle ofreflection with respect to the front of the ID document.

FIG. 2 depicts the ID document of FIG. 1 viewed from the front of the IDdocument in reflected light at having a second angle of reflection withrespect to the front of the ID document.

FIG. 3 depicts the ID document of FIG. 1 viewed from the front withlight transmitted through the dynamic window from the back to the frontof the ID document.

FIG. 4 depicts an ID document with a dynamic window viewed from thefront under UV light.

FIG. 5 is a cross-sectional view of the ID document of FIG. 1 takenthrough line A-A.

FIG. 6 is a cross-sectional view of the ID document of FIG. 1 takenthrough line B-B.

DETAILED DESCRIPTION

Identification (ID) documents described herein are made via a platenlamination process. The platen lamination process yields flat cards withlittle or no thermal stress. Surface interactions due to electric chargeand surface non-evenness are also reduced or eliminated, therebyimproving card transportation in the printer. The platen laminationprocess also allows for surface debossing in the final construct. Thislamination process reduces materials costs by eliminating the use ofadhesives. A dynamic window may be formed in any location on the IDdocument. As used herein, “dynamic window” generally refers to an insertin an ID document that appears to be transparent when viewed from afirst side (e.g., a front) of the identification document in lighttransmitted through the dynamic window from a second side (e.g., a back)of the identification document toward the first side (e.g., the front)of the identification document, and appears to be nontransparent whenviewed from a first side (e.g., a front) of the identification documentin light reflected from the dynamic window from the first side (e.g.,the front) of the identification document. The dynamic window hasoptically variable properties (e.g., an appearance that changes uponviewing under radiation with light of various wavelengths, upon viewingin reflected or transmitted light, upon viewing at a particular angle ofincident light, or the like. A wide variety of materials with a range ofoptical properties may be used in the dynamic window.

ID documents described herein are suitable for Dye Diffusion ThermalTransfer (D2T2) personalization, laser (e.g., YAG and CO₂)personalization, or both. These ID documents may be “over-the-counter”documents or “central issue” documents, and may be personalized ineither process. The ID documents may have transparency enhancementproperties. U.S. 2011/0057040, entitled “OPTICALLY VARIABLE PERSONALIZEDINDICIA FOR IDENTIFICATION DOCUMENTS” is incorporated by referenceherein with respect to various features and fabrication processesrelated to ID documents.

As used herein, “ID document” is broadly defined and intended to includeall types of ID documents, including, documents, magnetic disks, creditcards, bank cards, phone cards, stored value cards, prepaid cards, smartcards (e.g., cards that include one more semiconductor chips, such asmemory devices, microprocessors, and microcontrollers), contact cards,contactless cards, proximity cards (e.g., radio frequency (RFID) cards),passports, driver licenses, network access cards, employee badges, debitcards, security cards, visas, immigration documentation, national IDcards, citizenship cards, social security cards, security badges,certificates, identification cards or documents, voter registrationand/or identification cards, police ID cards, border crossing cards,security clearance badges and cards, legal instruments, gun permits,badges, gift certificates or cards, membership cards or badges, andtags. Also, the terms “document,” “card,” “badge” and “documentation”are used interchangeably throughout this disclosure. In addition, IDdocument can include any item of value (e.g., currency, bank notes, andchecks) where authenticity of the item is important, wherecounterfeiting or fraud is an issue, or both.

ID documents such as driver licenses can contain information such as aphotographic image, a bar code (which may contain information specificto the person whose image appears in the photographic image, and/orinformation that is the same from ID document to ID document), variablepersonal information, such as an address, signature, and/or birthdate,biometric information associated with the person whose image appears inthe photographic image (e.g., a fingerprint), a magnetic stripe (which,for example, can be on the a side of the ID document that is oppositethe side with the photographic image), and various security features,such as a security pattern (for example, a printed pattern comprising atightly printed pattern of finely divided printed and unprinted areas inclose proximity to each other, such as a fine-line printed securitypattern as is used in the printing of banknote paper, stockcertificates, and the like).

In the production of images useful in the field of identificationdocumentation, it may be desirable to embody into a document (such as anID card, driver license, passport or the like) data or indiciarepresentative of the document issuer (e.g., an official seal, or thename or mark of a company or educational institution) and data orindicia representative of the document bearer (e.g., a photographiclikeness, name or address). Typically, a pattern, logo or otherdistinctive marking representative of the document issuer will serve asa means of verifying the authenticity, genuineness or valid issuance ofthe document. A photographic likeness or other data or indicia personalto the bearer will validate the right of access to certain facilities orthe prior authorization to engage in commercial transactions andactivities.

As used herein, “identification” at least refers to the use of an IDdocument to provide identification and/or authentication of a userand/or the ID document itself. For example, in a conventional driverlicense, one or more portrait images on the card are intended to show alikeness of the authorized holder of the card. For purposes ofidentification, at least one portrait on the card (regardless of whetheror not the portrait is visible to a human eye without appropriatestimulation) preferably shows an “identification quality” likeness ofthe holder such that someone viewing the card can determine withreasonable confidence whether the holder of the card actually is theperson whose image is on the card. “Identification quality” images, inat least one instance, include covert images that, when viewed using theproper facilitator (e.g., an appropriate light source for covert images,an appropriate temperature source for thermochromic images, etc.),provide a discernable image that is usable for identification orauthentication purposes.

There are a number of reasons why an image or information on an IDdocument might not qualify as an “identification quality” image. Imagesthat are not “identification quality” may be too faint, blurry, coarse,small, etc. to be able to be discernable enough to serve anidentification purpose. An image that might not be sufficient as an“identification quality” image, at least in some environments, could,for example, be an image that consists of a mere silhouette of a person,or an outline that does not reveal what might be considered essentialidentification essential (e.g., hair color or eye color) of anindividual.

Certain images may be considered to be “identification quality” if theimages are machine readable or recognizable, even if such images do notappear to be “identification quality” to a human eye, whether or not thehuman eye is assisted by a particular piece of equipment, such as aspecial light source. For example, in at least one embodiment, an imageor data on an ID document can be considered to be “identificationquality” if it has embedded in it machine-readable information (such asdigital watermarks or steganographic information) that also facilitateidentification and/or authentication.

Further, in at least some embodiments, “identification” and“authentication” are intended to include (in addition to theconventional meanings of these words), functions such as recognition,information, decoration, and any other purpose for which an indicia canbe placed upon an article in the article's raw, partially prepared, orfinal state. Also, in addition to ID documents, techniques describedherein can be employed with product tags, product packaging, businesscards, bags, charts, maps, labels, and the like, particularly thoseitems including marking of a laminate or over-laminate structure. “IDdocument” thus is broadly defined herein to include these tags, labels,packaging, cards, etc.

“Personalization,” “personalized data,” and “variable” data are usedinterchangeably herein, and refer at least to data, characters, symbols,codes, graphics, images, and other information or marking, whether humanreadable or machine readable, that is (or can be) “personal to” or“specific to” a specific cardholder or group of cardholders.Personalized data can include data that is unique to a specificcardholder (such as biometric information, image information, serialnumbers, Social Security Numbers, privileges a cardholder may have,etc.), but is not limited to unique data. Personalized data can includesome data, such as birthdate, height, weight, eye color, address, etc.,that are personal to a specific cardholder but not necessarily unique tothat cardholder (for example, other cardholders might share the samepersonal data, such as birthdate). In at least some embodiments,personal/variable data can include some fixed data, as well.

For example, in at least some embodiments, personalized data refers toany data that is not pre-printed onto an ID document in advance, so suchpersonalized data can include both data that is cardholder-specific anddata that is common to many cardholders. Variable data can, for example,be printed on an information-bearing layer of the ID card using thermalprinting ribbons and thermal printheads. Personalized and/or fixed datais also intended to refer to information that is (or can be)cross-linked to other information on the ID document or to the IDdocument's issuer. For example, personalized data may include a lotnumber, inventory control number, manufacturing production number,serial number, digital signature, etc. Such personalized or fixed datacan, for example, indicate the lot or batch of material that was used tomake the ID document, what operator and/or manufacturing station madethe ID document and when, etc.

The terms “indicium” and “indicia” as used herein cover not onlymarkings suitable for human reading, but also markings intended formachine reading, and include (but are not limited to) characters,symbols, codes, graphics, images, etc. Especially when intended formachine reading, such an indicium need not be visible to the human eye,but may be in the form of a marking visible only under infra-red,ultra-violet or other non-visible radiation. Thus, in at least someembodiments, an indicium formed on any layer in an ID document may bepartially or wholly in the form of a marking visible only undernon-visible radiation. Markings including, for example, a visible“dummy” image superposed over a non-visible “real” image intended to bemachine read may also be used.

“Laminate” and “overlaminate” include (but are not limited to) film andsheet products. Laminates usable with at least some embodiments includethose which contain substantially transparent polymers or which havesubstantially transparent polymers as a part of their structure.Examples of suitable laminates include at least polyester,polycarbonate, polystyrene, cellulose ester, polyolefin, polysulfone, orpolyamide. Laminates can be made using either an amorphous or biaxiallyoriented polymer as well. The laminate can comprise a plurality ofseparate laminate layers, for example a boundary layer, a film layer, orboth.

The degree of transparency of the laminate can, for example, be dictatedby the information contained within the ID document, the particularcolors and/or security features used, etc. The thickness of the laminatelayers is not critical, although in some embodiments it may be preferredthat the thickness of a laminate layer be about 1-20 mil (about 25-500μm). Types and structures of the laminates described herein are providedonly by way of example, those skilled in the art will appreciate thatmany different types of laminates are suitable.

For example, in ID documents, a laminate can provide a protectivecovering for the printed substrates and provides a level of protectionagainst unauthorized tampering (e.g., a laminate would have to beremoved to alter the printed information and then subsequently replacedafter the alteration). The material(s) from which a laminate is made maybe transparent, but need not be. Laminates can include syntheticresin-impregnated or coated base materials composed of successive layersof material, bonded together via heat, pressure, or both. As describedherein, laminates may be fused polycarbonate structures formed in theabsence of adhesives. Laminates also include security laminates, such asa transparent laminate material with proprietary security technologyfeatures and processes, which protects documents of value fromcounterfeiting, data alteration, photo substitution, duplication(including color photocopying), and simulation by use of materials andtechnologies that are commonly available. Laminates also can includethermosetting materials, such as epoxies.

For purposes of illustration, examples illustrate various aspects usingimages that are representative of a bearer of an ID document (e.g., aphotographic likeness). However, virtually any indicium can be usable asan “image,” which is used herein to include virtually any type ofindicium.

Different image processing techniques may be used to preprocess anoriginal image that is to be printed as a covert and/or opticallyvariable image (using, for example, covert and/or optically variablemedia) depending on whether the tonality of image reproduction (e.g.,printing process) is bitonal (e.g., two tones such as black and white ora first color and second color) or monochromatic (e.g., shaded image,grayscale, etc.). Other optional factors to consider include the viewingmethods used with the image, such as reflectance, transmissivecharacteristics (e.g., UV glowing) and tactility. As used herein,“optically variable device” (OVD) generally refers to an image (e.g., aniridescent image) that exhibits various optical effects such as movementor color changes when viewed.

In some cases, an image may be in digital form, such as resulting frombeing digitally captured, e.g., via a digital camera, optical sensor,etc., or through scanning a photograph with a scanner, etc. In at leastsome embodiments, this captured image may be refined to produce anintermediate image, which can be transferred or printed (or used togenerate an image to be transferred or printed) to the ID document as acovert image.

In certain cases, bitonal images (e.g., black and white images), such asthose produced through mass-transfer thermal printing and laserxerography, may be implemented. Generally, in this embodiment, acaptured image is processed to bring out or otherwise enhance relevantfeatures found in the captured image. Relevant features of a human facemay include the face outline, nose and mouth pattern, ear outline, eyeshape, eye location, hairline and shape, etc., or any other feature(s)that have been deemed to be relevant for identification purposes (e.g.,particular features used with matching algorithms such as facialrecognition algorithms). Once identified, these featured can be“thickened” or otherwise emphasized. The emphasized features can thenform a digital version of a covert image, which can be transferred to anidentification card.

Dye diffusion thermal transfer printing (“D2T2”) and thermal transfer(also referred to as mass transfer printing) are two printing techniquesused to print information on identification cards. For example, D2T2 hasbeen used to print images and pictures, and thermal transfer has beenused to print text, bar codes, and single color graphics.

Dye diffusion is a thermal imaging technology that allows for theproduction of photographic quality images. In dye diffusion printing,one or more thermally transferable dyes (e.g., cyan, yellow, andmagenta) are transferred from a donor, such as a donor dye sheet or aset of panels (or ribbons) that are coated with a dye (e.g., cyan,magenta, yellow, black, etc.) to a receiver sheet (which could, forexample, be part of an ID document) by the localized application of heator pressure, via a stylus or thermal printhead at a discrete point. Whenthe dyes are transferred to the receiver, the dyes diffuse into thesheet (or ID card substrate), where the dyes will chemically be bound tothe substrate or, if provided, to a receptor coating. Typically,printing with successive color panels across the document creates animage in or on the document's surface. Dye diffusion can result in avery high printing quality, especially because the energy applied to thethermal printhead can vary to vary the dye density in the image pixelsformed on the receiver, to produce a continuous tone image. Dyediffusion can have an increased cost as compared to other methods,however, because of the special dyes needed and the cost of dyediffusion ribbons. Also, the quality of dye diffusion printed image maydepend at least on an ability of a mechanical printer system toaccurately spatially register a printing sequence, e.g., yellow,magenta, cyan, and black.

Another thermal imaging technology is thermal or mass transfer printing.With mass transfer printing, a material to be deposited on a receiver(such as carbon black, referred to by the symbol “K”) is provided on amass transfer donor medium. When localized heat is applied to the masstransfer donor medium, a portion (mass) of the material is physicallytransferred to the receiver, where it sits “on top of” the receiver. Forexample, mass transfer printing often is used to print text, bar codes,and monochrome images. Resin black mass transfer has been used to printgrayscale pictures using a dithered gray scale, although the image cansometimes look coarser than an image produced using dye diffusion.However, mass transfer printing can sometimes be faster than dyediffusion, and faster printing can be desirable in some situations.

Printing of black (“K”) can be accomplished using either dye diffusionor mass transfer. For example, black monochrome “K” mass transferribbons include Kr (which designates a thermal transfer ribbon) and Kd(which designates dye diffusion). The black that is created by dyediffusion is referred to as “process black”—i.e., a combination of cyan,yellow and magenta to create black. The K panel is a carbon black entityand is a real “black.” Process black will allow IR to pass through,while K will not. The term “D2T2” is a combination of the phrases “DyeDiffusion” (D2) and “Thermal Transfer” (T2); T2 is a mass transferribbon panel and performs in a similar fashion as any other masstransfer technology. Both dye diffusion and thermal ink have beencombined in a single ribbon (e.g., D2T2 ribbon), which is the well-knownYMCK (Yellow-Magenta-Cyan-Black) ribbon. Another panel containing aprotectant (“P”) or laminate (typically a clear panel) also can be addedto the YMCK ribbon.

Commercial systems for issuing ID documents are of two main types,namely so-called “central” issue (CI), and so-called “on-the-spot” or“over-the-counter” (OTC) issue.

CI type ID documents are not immediately provided to the bearer, but arelater issued to the bearer from a central location. For example, in onetype of CI environment, a bearer reports to a document station wheredata is collected, the data are forwarded to a central location wherethe ID document is produced, and the ID document is forwarded to thebearer, often by mail. Another illustrative example of a CI assemblingprocess occurs in a setting where a driver passes a driving test, butthen receives her license in the mail from a CI facility a short timelater. Still another illustrative example of a CI assembling processoccurs in a setting where a driver renews her license by mail or overthe Internet, then receives a driver license card through the mail.

In contrast, a CI assembling process is more of a bulk process facility,where many cards are produced in a centralized facility, one afteranother. For example, picture a setting where a driver passes a drivingtest, but then receives her license in the mail from a CI facility ashort time later. The CI facility may process thousands of cards in acontinuous manner.

Centrally issued ID documents can be produced from digitally storedinformation and generally include an opaque core material (also referredto as “substrate”), such as paper or plastic, sandwiched between twolayers of clear plastic laminate, such as polyester, to protect theaforementioned items of information from wear, exposure to the elementsand tampering. The materials used in such CI ID documents can offerdurability. In addition, centrally issued digital ID documents generallyoffer a higher level of security than OTC ID documents because theyoffer the ability to pre-print the core of the CI ID document withsecurity features such as “micro-printing,” ultra-violet securityfeatures, security indicia and other features currently unique tocentrally issued ID documents.

In addition, a CI assembling process can be more of a bulk processfacility, in which many ID documents are produced in a centralizedfacility, one after another. The CI facility may, for example, processthousands of ID documents in a continuous manner. Because the processingoccurs in bulk, CI can have an increase in efficiency as compared tosome OTC processes, especially those OTC processes that runintermittently. Thus, CI processes can sometimes have a lower cost perID document, if a large volume of ID documents are manufactured.

In contrast to CI ID documents, OTC ID documents are issued immediatelyto a bearer who is present at a document-issuing station. An OTCassembling process provides an ID document “on-the-spot”. Anillustrative example of an OTC assembling process is a Department ofMotor Vehicles (“DMV”) setting where a driver license is issued toperson, on the spot, after a successful exam. In some instances, thevery nature of the OTC assembling process results in small, sometimescompact, printing and card assemblers for printing the ID document. Itwill be appreciated that an OTC card issuing process can be by itsnature an intermittent process in comparison to a continuous process.

OTC ID documents of the types mentioned above can take a number offorms, depending on cost and desired features. Some OTC ID documentscomprise highly plasticized poly(vinyl chloride) or have a compositestructure with polyester laminated to 0.5-2.0 mil (about 13-51 μm)poly(vinyl chloride) film, which provides a suitable receiving layer forheat transferable dyes which form a photographic image, together withany variant or invariant data required for the identification of thebearer. These data are subsequently protected to varying degrees byclear, thin overlay patches (0.125-0.250 mil, or about 3-6 μm) appliedat the printhead, holographic hot stamp foils (0.125-0.250 mil, or about3-6 μm), or a clear polyester laminate (0.5-10 mil, or about 13-254 μm)supporting common security features. These last two types of protectivefoil or laminate sometimes are applied at a laminating station separatefrom the printhead. The choice of laminate dictates the degree ofdurability and security imparted to the system in protecting the imageand other data.

One response the counterfeiting of ID documents includes the integrationof verification features that are difficult to copy by hand or bymachine, or which are manufactured using secure and/or difficult toobtain materials. One such verification feature is the use in the IDdocument of a signature of the ID document's issuer or bearer. Otherverification features have involved, for example, the use of watermarks,biometric information, microprinting, covert materials or media (e.g.,ultraviolet (UV) inks, infrared (IR) inks, fluorescent materials,phosphorescent materials), optically varying images, fine line details,validation patterns or marking, and polarizing stripes. Theseverification features are integrated into an ID document in various waysand they may be visible or invisible (covert) in the finished card. Ifinvisible, they can be detected by viewing the feature under conditionswhich render it visible. At least some of the verification featuresdiscussed above have been employed to help prevent and/or discouragecounterfeiting.

Covert security features are those features whose presence is notvisible to the user without the use of special tools (e.g., UV or IRlights, digital watermark readers) or knowledge. In many instances, acovert security feature is normally invisible to a user. Sometechnologies that involve invisible features require the use ofspecialized equipment, such as a detector or a device capable of readingdigital watermarks. One type of covert security feature is the printingof information (images, designs, logos, patterns, text, etc.) in amaterial that is not visible under normal lighting conditions, but canbe viewed using a special non-visible light source, such as anultraviolet (UV) or infrared (IR) light source. Use of UV and/or IRsecurity features can be advantageous because although the devices (forexample, UV and/or IR light sources) required to see and use suchfeatures are commonly available at a reasonable cost, the ability tomanufacture and/or copy at least some implementations of such featuresis far less common and can be very costly. UV and IR based covertsecurity features thus can help deter counterfeiters because thefeatures cannot be copied by copiers or scanners and are difficult tomanufacture without the requisite know-how, equipment, and materials.

Many images, such as color images, are formed by subtractive techniques,e.g., light is passed through absorbing dyes and the combination of dyesproduce an image by sequentially subtracting cyan, magenta, and yellowcomponents to provide the full color image. In the case of a UVfluorescing image, the UV image is formed by light emitting fromfluorescing dyes or pigments as they are activated by a UV light orenergy source. A UV image can be imparted to an ID document via methodssuch as thermal transfer or D2T2.

Regardless of whether the UV materials are imparted via D2T2 or masstransfer panel, both panels produce transmissive images—the masstransfer panel produces a bitonal (e.g., two tone) image and the dyesublimation panel produces a monochromatic (or shaded) image.

Color shifting and other optically variable pigments, inks, dyes, andcolorants (collectively “optically variable media”) have a feature ofappearing to change color as the viewing angle of an observer changes(or as the angle of incident light striking the media changes).Optically variable media have been used on security documents, such asidentification cards, credit cards, checks, title documents, currency,etc. The optically variable property provides several advantages whenused on security documents: (a) the presence and appearance of opticallyvariable quality provides another “check” or method to authenticate thesecurity document; (b) optically variable media are generally moredifficult for a layman to obtain and use properly, thus helping toprevent (or at least limit) forgery and to make forgeries and/oralteration easier to detect; and (c) photocopiers and scanners generallywill not reproduce many types of optically variable media, helping toreduce unauthorized reproduction or counterfeiting of such documents.

Several methods exist to create optically variable media and to applysuch media to security documents. One method involves dispersing in amedium (e.g., paint or ink) a plurality of relatively small particles(typically flakes) that have specific optical properties. In oneexample, a security document includes a plurality of thin film layers,each film having a particular color and/or optical property. In somecases, media having optically variable properties include particlescomprising flat, irregularly shaped mica platelets coated with titaniumdioxide and/or iron oxide. These particles, when dispersed in media, cangive a generally “pearlescent” effect, with smaller particles producinga “satin” effect and larger particles producing a “glitter” effect. Inmany instances, optically variable media are incorporated into amaterial such as a laminate layer or overlaminate layer, providing anoptically variable indicia that overlays other information on the card.Generally, such an optically variable indicium contains “fixed” or“invariable” data (information that is the same from ID document to IDdocument).

In some cases, it is advantageous to print variable or personal UVinformation at the time of ID document personalization, in one, two, orthree UV colors, especially images that have a high enough quality to beused for authentication and/or identification. It is also advantageousif the same information is printed in a visible and invisible (e.g., UV)form at substantially the same time or at substantially the sameprinting step, where the covert image would be “identification quality.”

An ID document having a window as described herein is fabricated in aplaten lamination process, in which component layers of the ID documentare fused together with heat, pressure, or both, without adhesives.Platen lamination allows the formation of flat cards with little or nothermal stress, as compared to roll lamination that creates stresses bystretching and laminating in a non-uniform manner. Platen laminationalso reduces or eliminates surface interactions due to electrical chargeand surface non-evenness, thereby improving card transportation in thecard printer. One or more of the component layers may be preprinted(e.g., with invariable data). The resulting ID document is referred toherein as a “card blank” or “blank card.” The invariable data may bepresent as microprint or added in an offset printing process on one ofthe layers used to construct the card blank. The resulting ID documentis durable and solid, suitable for OTC or CI issue, and has an expecteduseful lifetime of at least 10 years.

The dynamic window, an optically functional element that deliversdifferent visual characteristics when viewed under different lightingconditions, is formed during fabrication of the card blank. Securityfeatures may be added by the printing process, the laminating process,or both in an OTC or CI process. Thus, an ID document with a window asdescribed herein may be used as an OTC issue, with variable features(e.g., a photograph of the cardholder) printed (e.g., with opticallyvariable media) on the window, other portions of the card blank, or bothbefore lamination. As such, security features involving variable datamay be added during an OTC process at an issuing location.

FIG. 1 depicts ID document 100 with dynamic window 102 viewed inreflected light. As depicted, dynamic window 102 is circular, but may beany shape (e.g., elliptical, rectangular, square, irregular, etc.).Dynamic window 102 has coating 104. As described with respect to FIG. 1,coating 104 is on a back of dynamic window 102, corresponding to a backof ID document 100. In some cases, dynamic window 102 has more than onecoating (e.g., a first coating on a front of the dynamic window and asecond coating on the back of the dynamic window). Coating 104 is anoptically variable coating. Dynamic window 102 has a first visualcharacteristic when viewed from front 106 of ID document 100 inreflected light and a second visual characteristic when backlit (i.e.,viewed from front 106 with light transmitted through dynamic window 102from back 108 toward front 106). When viewed in reflected light, theprimary light source is on the same side of ID document as the viewer.When backlit, the primary light source is on the opposite side of the IDdocument as the viewer. The first visual characteristic and the secondvisual characteristic, as well as the difference between the firstvisual characteristic and the second visual characteristic, aredistinguishable with the unassisted human eye. The appearance of dynamicwindow 102 may vary, for example, based on the properties of coating 104as well as a function of the location of the primary light source. Insome cases, dynamic window 102 may exhibit a special effect (e.g., goldmetallic or silver metallic) based upon coating 104.

As described with respect to FIG. 1, image 110 is printed on orsuperimposed above a front side of dynamic window 102 (e.g., on a layerof the laminate between the front of identification document 100 and thecore layer). In some cases, ID document 100 includes more than one image110 (e.g., a first image as described with respect to FIG. 1 and asecond image on a back of dynamic window 102 or on a layer of thelaminate between the back of identification document 100 and the corelayer). Image 110 may include variable data (e.g., a photographic imageof the cardholder) printed in an OTC or CI process. As depicted in FIG.1, image 110 is understood to be a replica of primary color image 112.In some cases, optically variable ghost image 114, described below inmore detail, may also be present. When viewed from front 106 of IDdocument 100 in reflected light having a first angle of reflection,dynamic window 102 has a first visual appearance (e.g., dynamic windowappears colored, opaque, reflective, metallic, or the like, based on theproperties of coating 104), which serves as a background for image 110.Optically variable ghost image 114 may also be most visible in reflectedlight at this angle of reflection. When viewed from front 106 of IDdocument 100 in reflected light at a second angle of reflection (e.g.,as in FIG. 2), image 110 appears to be on a muted background. In oneexample, when dynamic window 102 has a gold metallic appearance whenviewed in reflected light at a first angle of reflection with respect tofront 106, image 110 appears to be overlaid on an opaque gold metallicbackground, due at least in part to a high ratio of reflected totransmitted light. When viewed in reflected light at a second angle ofreflection, image 110 appears to be overlaid on a muted gold metallicbackground, due at least in part to a relatively lower ratio ofreflected to transmitted light.

When ID document 100 is viewed from back 108 in reflected light having afirst angle of reflection (i.e., with the viewer looking at the back ofthe ID document and the primary light source on the same side of the IDdocument as the viewer), image 110 is not visible, and dynamic window102 has a uniform, opaque appearance determined by coating 104 on thedynamic window, due at least in part to a high ratio of reflected totransmitted light. When ID document 100 is viewed from back 108 inreflected light having a second angle of reflection, image 110 isvisible on dynamic window 102, and the image and the dynamic window bothhave a muted appearance, due at least in part to a relatively lowerratio of reflected to transmitted light. In one example, when dynamicwindow 102 has a bright gold metallic appearance when viewed inreflected light from front 106 of ID document 100, the dynamic windowhas a solid bright gold metallic appearance when viewed in reflectedlight at a first angle of reflection from back 108 of the ID document,and image 110 is not visible. When viewed in reflected light having asecond angle of reflection from back 108 of ID document 100, image 110and dynamic window 102 have a muted appearance.

An ID document, such as ID document 100, may have one or more of thefollowing additional features generally known in the art: Guillochesecurity design, micro-print, microprint with deliberate error, securityindicia, laser perforation, split fountain printing, IDMARC, variablemicro-script, altered font, overlapping data, UV printed variable data,redundant data, one-dimensional bar code, two-dimensional bar code,tri-color optically variable device, magnetic stripes, digitalwatermarks, covert image, and biometric information (e.g., fingerprint,etc.). Each of these features, is optional, and the positioning orembedding of these features is variable.

FIG. 2 depicts ID document 100 viewed from the front in reflected lightat an angle of reflection that differs from that depicted in FIG. 1. Asdepicted in FIG. 2, optically variable ghost image 114 is less visibleat the angle of reflection in FIG. 2 than at the angle of reflection inFIG. 1. As depicted, optically variable ghost image 114 is a full size(i.e., the same size as color image 112) pixelated image that overlaysimage 112. Tilting ID document 100 in reflected light causes opticallyvariable ghost image 114 to appear more or less visible, and also causesdynamic window 102 and image 110 to appear more or less muted.

Optically variable ghost image 114 can be a screened-back or “ghost”version of color image 112. In some cases, optically variable ghostimage 114 is a color or grayscale halftone version of the color image.Optically variable ghost image 114 is also preferably visible undernormal viewing conditions in reflected light, but more visible at afirst angle of reflection (e.g., as in FIG. 1) than a second angle ofreflection (e.g., as in FIG. 2). A covert image may also correspond toimage 112, and may not be visible under “normal” viewing conditions. Inone embodiment, a covert image is an ultraviolet (UV) image, meaningthat it glows (e.g., visibly fluoresces or emits radiation) in responseto appropriate UV stimulation. In some implementations, a covert imagefluoresces in the UV spectrum upon excitation with visible light. Acovert image may be generally imperceptible under normal (e.g.,non-ultraviolet or non-angled) viewing conditions.

As described herein, an optically variable ghost image may generally beprinted using optically variable ink. When an optically variable ghostimage is generated using any one of known methods, the opticallyvariable ghost image may have an appearance that is analogous to aphotographic “inverse” or “negative” of the visible ghost image. Thismay be referred to as one type of a “mirror-like image,” although, ofcourse, “true” mirror images of a given image, such the image of a facereflected from an actual mirror, in fact show a backwards image. Onereason this may be referred to as a “mirror-like” image, for at leastsome embodiments, is because at least some of the optically variableinks used to print the optically variable device (OVD) create a“mirror-like” sheen or luster when printed. Another reason this isreferred to as a “mirror-like” image, for at least some embodiments, isthe reflective quality of the image. Yet another reason this is referredto as a “mirror-like” image is because, in at least some embodiments,the image can have an appearance that is similar is a photographicinverse or negative of the visible image, except printed using opticallyvariable ink.

Close alignment of the OVD to a corresponding similar visible image,however, is optional. In at least some embodiments an OVD can be appliedso as to partially overlay a variable indicium on the ID document, andthe variable indicium need not be the same indicium as the OVD. Further,an OVD can be applied to an ID document so that it does not overlay avariable indicium on an ID document.

In one example, a location for an OVD can be selected that permits theOVD to be printed in such a way (described further herein) that it ispossible to obtain an appearance of a “flipping” image of the OVD whenthe ID document is viewed at different angles. This advantageously maybe done by printing over an area of the card that does not containinformation that would interfere with the appearance of the OVD. Thearea need not be a substantially blank area of the ID document; forexample, the area could contain fixed indicia such as background colors,fine line printing, artwork, scrolls, etc.

In one embodiment, a covert image is an infrared (IR) image, meaningthat it glows (e.g., visibly fluoresces or emits radiation) in responseto appropriate IR stimulation. In one embodiment, a covert image is athermachromic image, meaning that it becomes visible only when the image(or entire ID document 100) is subject to a predetermined change intemperature, such as by heating or cooling. In one embodiment, a covertimage is an optically variable image, meaning that the covert image ismost visible when viewed at a particular angle. In one embodiment, acovert image is formed using a material such as a ferrofluid (availablefrom FeroTec of Nashua, N.H.). Ferrofluids are responsive to magneticfields, and can be used to produce covert images that become visiblewhen an appropriate magnetic field is applied to the ferrofluid.

In one embodiment, a covert image is a combination of any one or more ofUV, IR, thermachromic, ferrofluidic, and optically variable images. Forexample, a covert image can be both a UV and a thermachromic image byprinting the card area, using the methods described herein, with both UVand thermachromic inks, meaning that when subject to appropriatestimulation, the normally “blank” area of the card will display either aUV image (if appropriate UV stimulation is provided) or a thermachromicimage (if appropriate temperature is provided). Those skilled in the artwill appreciate that many combinations are possible. It is evenenvisioned that combination type inks, such as UV thermachromic inks(meaning inks that, to display an image, require both UV and appropriatetemperature), the methods described herein will be usable with suchinks.

In one embodiment, a steganographic code is embedded into a covertimage. One form of steganographic encoding is digital watermarking.Digital watermarking is a process for modifying physical or electronicmedia to embed a machine-readable code into the media. The media may bemodified such that the embedded code is imperceptible or nearlyimperceptible to the user, yet may be detected through an automateddetection process. In some embodiments, the ID document includes two ormore digital watermarks.

Digital watermarking systems typically have two primary components: anencoder that embeds the digital watermark in a host media signal, and adecoder that detects and reads the embedded digital watermark from asignal suspected of containing a digital watermark (a suspect signal).The encoder embeds a digital watermark by altering the host mediasignal. The reading component analyzes a suspect signal to detectwhether a digital watermark is present. In applications where thedigital watermark encodes information, the reader extracts thisinformation from the detected digital watermark. The reading componentcan be hosted on a wide variety of tethered or wireless reader devices,from conventional PC-connected cameras and computers to fully mobilereaders with built-in displays. By imaging a watermarked surface of thecard, the watermark's “payload” can be read and decoded by this reader.

Returning to the present implementation, a digital watermark may beembedded in a covert image. For purposes of illustration, assume thatthe covert image is a printed UV image. A watermark detector can onlyread the covert UV watermark if ID document 100 is subject toappropriate UV stimulation at the same time that the host ID document ispresented to the watermark detector. This provided additional securityto the ID document 100, because even if a counterfeiter is able toaccess UV inks to print a bogus covert image, the bogus covert imagewill not contain the embedded digital watermark. Of course, merephotocopying or scanning of ID document 100 will similarly frustrate thecounterfeiter, who will be unable to reproduce, through scanning orphotocopying, either the covert image or the watermark containedtherein.

In one embodiment, the watermark embedded in a covert image may includea payload or message. The message may correspond, e.g., to the IDdocument number, printed information, issuing authority, biometricinformation of the bearer, and/or database record, etc. The watermarkembedded in the covert image may also include an orientation component,to help resolve image distortion such as rotation, scaling andtranslation. In at least one embodiment, two or more watermarks areembedded in the optically variable device (OVD) image.

In further embodiments, the watermark embedded in a covert imagecorresponds to information printed on the ID document, or to informationcarried by a second watermark embedded elsewhere on the ID document(e.g., background pattern, image 112, etc.).

Methods for printing an optically variable image of variable data (e.g.,data that can differ from card to card) onto the ID document, where theoptically variable image has a metallic, iridescent, pearlescent, or“mirror-like” sheen or luster at a particular viewing angle, but whichstill enables the indicia to be perceived at the particular angle. Theoptically variable indicia is essentially invisible when the ID documentis viewed from angles other than the particular angle. This opticallyvariable image can comprise any type of indicium: images (e.g., aphotograph), characters (e.g., a birthdate), graphics, etc. Inparticular, this optically variable image can comprise personalized data(e.g., data specific to a particular holder of an ID document orspecific to a group of ID documents).

In one embodiment of this aspect, an optically variable image is printedat the time of card personalization using a specially configured ribbonadapted for D2T2 and/or mass transfer printing. In one embodiment, theoptically variable image of variable data is printed onto an area of theID document that contains little or no other indicia, such that when theID document is viewed at a first angle, the optically variable image isnot visible, but when the document is viewed at a second angle, itbecomes visible.

In an advantageous example, ID document 100 will include at least onevariable indium (such as a bearer image, signature, ghost image,birthdate, etc.) that is visible to an unassisted human eye, so thatsuch a variable feature may be compared to the optically variableindicia of variable information described in the following paragraph, todetect counterfeiting and/or alteration.

If an optically variable ink is used, and the image (or other indicium)is printed as described herein, the optically variable image may appearto be a first metallic, iridescent, or pearlescent color at a firstangle and will appear to be a either not substantially visible or adifferent color (e.g., in some embodiments, a second metallic,iridescent, or pearlescent color) at a second angle. As will be furtherdescribed herein, many other embodiments of the “mirror-like opticallyvariable device” can be created. A few examples of “optically variableminor image” include:

printing a dithered or continuous-tone version of an indicium in anoptically variable ink;

printing a dithered or continuous-tone version of an indicium in anoptically variable ink directly over and in alignment with the sameindicium printed in a non-optically variable ink, wherein the indiciumin optically variable ink becomes visible at certain viewing angles andthe non-optically variable indicium is not visible at those viewingangles;

printing a first dithered or continuous-tone version of an indicium inan optically variable ink directly over and in alignment with a secondindicium (which can be the same indicium) printed using a covertmaterial (e.g., ultraviolet (UV) ink, infrared (IR) ink, thermachromicink, combinations of UV, IR and/or thermachromic, etc.) and optionallyin alignment with a third indicium (which can be an indicium that is thesame as either or both of the first and second indicia or which can be athird indicium) printed using a non-covert, non-optically variablematerial;

printing a first dithered or continuous-tone version of an indicium in afirst optically variable ink interleaved with a second dithered orcontinuous tone version of an indicium in a second optically variableink, where the first and second dithered versions are different enoughthat a naked human eye can see a shift in the indicium and/or its coloras the viewing angle of the image is shifted;

printing a dithered or continuous-tone version of an indicium using morethan one optically variable ink, where a first portion of the pixels inthe indicium are printed in a first color of optically variable ink anda second portion of the pixels in the indicium are printed using asecond color of optically variable ink, wherein the overall appearanceof the indicium printed using the two or more colors of opticallyvariable ink can appear to have a luster or sheen as the indicium isviewed from different viewing angles;

printing a dithered or continuous tone version of an indicium using aplurality of colors of optically variable ink, where the indicium isformed on a portion of the ID document that does not contain otherindicia; and/or

printing an indicium that includes microtext variable data using anoptically variable ink, where the microtext variable data is structuredand arranged to appear, to the unassisted human eye, to be an opticallyvariable ornamental or decorative element on the another indicium or onthe ID document itself (e.g., a border around an image of an individual,a line (or pattern or lines) disposed near fixed indicia on the IDdocument, a border or design around another security feature, such as ahologram, etc.).

FIG. 3 depicts a top view of ID document 100 of FIG. 1 when the IDdocument is backlit, such that the ID document is between the viewer andthe primary light source, and light is transmitted through dynamicwindow 102 from back 108 toward front 106. As seen in FIG. 3, dynamicwindow 102 has a second visual appearance, which is different from thefirst visual appearance as depicted in FIG. 1. That is, dynamic window102 appears to be transparent (coating 104 is not visible), and providesa transparent background for image 110 at all viewing angles. Inaddition, when dynamic window 102 is backlit, laser engraving 116becomes visible. When ID document 100 is viewed from back 108 with lighttransmitted through dynamic window 102 from front 106, dynamic window102 has a transparent appearance, such that image 110 appears on atransparent background at all viewing angles.

In some cases, image 110 on dynamic window 102 may be a bitonal image ora covert or optically variable image. When image 110 is an opticallyvariable ghost image and ID document 100 is viewed from front 106 inreflected light, dynamic window 102 has the first visual appearance andthe optically variable ghost image is visible when the ID document isviewed in reflected light at a particular angle of reflection. Whenimage 110 is an optically variable ghost image and ID document 100 isbacklit, dynamic window 102 appears to be transparent, and the opticallyvariable ghost image is not visible. That is, when image 110 is anoptically variable ghost image, like dynamic window 102, it is visiblein reflected light at greater and lesser intensity based on angle ofreflection, but is not visible in transmitted light.

FIG. 4 depicts ID document 120 viewed from front 106 under UV light. Asdepicted in FIG. 4, optically variable ghost image 114 is responsive toUV light. In one example, optically variable ghost image 114 has a blueglow under UV light. In addition, dynamic window 102 also has a UVresponse, and appears to glow under UV light.

FIG. 5 is a cross-sectional view of ID document 100 taken along line A-Aof FIG. 1. ID document 100 includes core layer 202, tie layers 204, 204′on either side of the core layer, and structural layers 206, 206′ on theouter side of tie layers 204, 204′, respectively. Core layer 202 isopaque, houses the dynamic window, and may be preprinted on one or bothsides (e.g., with invariable data). One or more of tie layers 204, 204′may also be preprinted, engraved, or both. Tie layers 204, 204′typically include multiple co-extruded layers and promote bondingbetween core layer 202 and structural layers 206, 206′. Structurallayers 206, 206′ provide durability as well as stiffness and flatness.Tamper-evident (TE) patterns may be coated onto structural layers 206,206′ via gravure. After assembly (e.g., manually or via machine), corelayer 202, tie layers 204, 204′, and structural layers 206, 206′ arelaminated in a platen lamination process to yield card blank 208, formedin the absence of adhesive compositions. The platen lamination processfacilitates debossing, as well as the flatness, superior surface finish,and desired polish for card blank 208.

Receiver layers 210, 210′ may be coated on the outer side of eachstructural layer 206, 206′, respectively, and may be bonded to thestructural layers via solvent dissolution, thereby becoming part of thestructural layers. Tamper-evident patterns may be coated on an undersideof one or more of receiver layers 210, 210′. Receiver layers 210, 210′allow good image replication (e.g., via D2T2) as well as debossing.Patterns formed by plate debossing go through the D2T2 receiver layerand into the structural layer underneath, thereby providing protectionof the image, photo, or text (as applicable) from tampering orcounterfeiting. Overlaminate layers 212, 212′ may be coated on receiverlayers 210, 210′, respectively, after personalization. Overlaminatelayer 212 represents front 106 of ID document 100, and overlaminatelayer 212′ represents back 108 of the ID document. Receiver layers 210,210′ and overlaminate layers 212, 212′ are not considered to be part ofthe card blank. Thus, card blank 208 has five layers, including corelayer 202, tie layers 204, 204′, and structural layers 206, 206′.

Core layer 202 is typically opaque. Suitable materials for core layer202 include white poly(vinyl chloride) (PVC), polyester, polycarbonate,polystyrene, and the like. TESLIN and other polymers that are capable ofz-axis tear out and are immiscible with other polymers are typically notsuitable for core layer 202. A thickness of core layer 202 is typicallyin a range of 5 to 10 mil (about 125 to 250 μm). Fixed indicia may beprinted (or pre-printed) on core layer 202. The core layer in at leastsome embodiments is formed using a material adapted to be printable ormarkable (e.g., by laser marking) using a desired printing/markingtechnology. Materials that are printable can include, as an example,materials such as polyolefin, polyester, polycarbonate (PC), PVC,plastic, polyethylene terephthalate (PET), polyethylene terephthalateglycol-modified (PETG), polyethylene terephthalate film (PETF), andcombinations thereof. However, materials that can split in the z-axisare typically not suitable. Many other materials are, of course,suitable, as those skilled in the art will appreciate. In anadvantageous embodiment, core layer 202 is substantially opaque, whichcan enable printing on one side to be not viewable from the other side,but opacity is not required. In some embodiments, it may, in fact, beadvantageous that core layer 202 be substantially transparent. The colorof the core layer 202 may vary, but in an advantageous embodiment thecore layer is colored to provide a good contrast with indicia printed(or otherwise formed) thereon. In one example, core layer 202 is lightin color, thereby allowing good contrast with dark indicia. In anotherexample, core layer 202 is dark in color, thereby allowing good contrastwith light indicia.

Tie layers 204, 204′ typically include multiple layers of chemicallymodified resins with reactive moieties (e.g., isocyanates) attached tothe base resin. The reactive moieties in an outer layer of a tie layerare selected form covalent bonds with the layer in contact with the tielayer during lamination. Suitable materials for tie layers 204, 204′ arecompatible with other materials in the ID document and include PETG andPC. A thickness of tie layers 204, 204′ is typically in a range of 2 to6 mil (about 50 to 150 μm). Thickness, composition, or both of tielayers 204 and 204′ may be the same or different. In some cases, a laserengraved image (e.g., a hologram or KINEGRAM) is formed in one or moreof tie layers 204, 204′ (e.g., in tie layer 204). The laser engravingmay be such that the dynamic window in core layer 202 is not affected bythe laser engraving (e.g., the optically variable coating on the dynamicwindow is not ablated or removed by the laser engraving).

Suitable materials for structural layers 206, 206′ include PC,polyethers, polyphenoxides, polyphenols, polyesters, polyurethanes, andthe like. Structural layers 206, 206′ may be sensitized to accept laserengraving. A thickness of structural layers 206, 206′ is typically in arange of 2 mil to 10 mil (about 50 μm to about 250 μm). Thickness,composition, or both of structural layers 206, 206′ may be the same ordifferent.

Suitable materials for receiver layers 210, 210′ include PC (e.g.,non-sensitized), coated with, for example, modified PVC withantioxidants. The receiver coating allows good image replication andusing deboss patterns promotes protection of printed features (e.g.,images, text) from tampering, counterfeiting, or both. A thickness ofreceiver layers 210, 210′ is typically in a range of 4 to 10 mil (about100 μm to about 250 μm). Thickness, composition, or both of receiverlayers 210, 210′ may be the same or different.

If two adjacent layers are made of substantially the same material(e.g., polycarbonate), they may be laminated together into a singlestructure, as understood by those skilled in the art. Similarly, if alaminate and an overlaminate are both made of the same material (e.g.,polycarbonate), they can be laminated into a single structure.

If the laminate is made of a material (e.g., PET) that is not itselfcapable of being imaged using a given printing or marking technology(e.g., D2T2), layers or coatings may be applied to the laminate to makeit printable and/or markable. For example, in one embodiment, thelaminate is coated with a coating that enhances absorption of laserenergy. In another example, an image receiving layer that improves D2T2printing is applied to the laminate. Variable data (e.g., signature,ghost image, fingerprint, etc.) may be printed a receiver layer, such asby D2T2, mass transfer printing, and/or laser engraving. In oneimplementation, optically variable indicia of variable data are formedon the laminate by printing the laminate with a conventional D2T2 YMCtype of ribbon modified by the addition of a panel containing athermally transferable thermally transferable optically variablepigment, such as ink or dye.

A window in an ID document described herein, such as dynamic window 102in ID document 100, may be formed by defining an opening in the corelayer (e.g., dye cutting the core layer) and positioning a plastic layerhaving the same dimensions as the opening and the same thickness as thecore layer in the opening, such that the plastic layer is inlaid in thecore layer. Suitable materials for the plastic layer include PC, PVC,PETG, and the like. The plastic layer is typically clear plastic havingone or more optically functional coatings or devices (e.g., an opticallyvariable coating, a metallic digitally mastered hologram, or both) onone or both sides. The optically functional coatings or devices may beapplied to the plastic layer (e.g., before the plastic layer ispositioned in the core layer) by methods known in the art, includingsputtering, vacuum depositing, solution coating, and the like. Before orafter application of the optically functional coatings or devices, theplastic layer is sized to fit in the opening in the core layer. Thecoated plastic layer is positioned in the opening in the core layer(e.g., as an insert) to yield the dynamic window.

FIG. 6 depicts a cross-sectional view of ID document 100 along line B-Bof FIG. 1. In one example, card blank 208 is formed by forming anopening in core layer 202 and positioning dynamic window 102 in theopening. In one example, dynamic window 102 formed from clear 6 mil(about 150 μm) plastic film (e.g., PC, PVC, PETG, or the like) withcoating 104′ on the side of dynamic window 102 facing front 106 of IDdocument 100, coating 104 on the side of dynamic window 102 facing back108 of ID document 100, or both. Coatings 104 and 104′ may be the sameor different. In one example, coating 104 is gold and coating 104′ isblue. As used herein, “coating 104, 104” refers to coating 104, coating104′, or both. In some cases, coating 104, 104′ includes a metallicdigitally mastered hologram.

Dynamic window 102 is typically heat-stable, such that opticalproperties are maintained during lamination. In some cases, dynamicwindow 102 is laser sensitive, such that laser engraving may be used toengrave an image, text, or a combination thereof on the film. Dynamicwindow 102 may be laser sensitive to the exclusion of other componentsof ID document 100. In certain cases, a metallic KINEGRAM may be printedon dynamic window 102 and a laser (e.g., a YAG laser or CO₂ laser) maybe used to laser write variable data into the dynamic window beforefabrication of the card blank. In still other cases, an opticallyvariable device (OVD) (e.g., a metallic KINEGRAM or hologram) may beprinted on either side of dynamic window 102 or on another layer of theID document and superimposed on either side of the dynamic window.

Fabricating card blank 208 corresponding to ID document 100 as describedherein is achieved by assembling the layers of the card blank by hand ormachine and plate laminating by pressure, heat, or both by methods andequipment generally known in the art (e.g., buckle laminators). Coating104, 104′ may be applied to dynamic window 102 before or after placementof the dynamic window in core layer 202. The dynamic window is typicallyheld in the core layer by friction or ultrasonically welded in place.Thickness of an exemplary ID document is typically 30±3 mil (about760±76 μm). These ID documents are generally fabricated to meetapplicable ISO and AAMVA standards.

Coating 104, 104′ is formed by application of a dispersion to thesubstrate used to form dynamic window 102. The dispersion typicallyincludes an inorganic pigment, a solvent, and a binder, and isformulated to achieve a viscosity suitable for coating in a coatingprocess (e.g., at least 50 wt % solvent, at least 10 wt % binder, and atleast 10 wt % pigment; or 50-70 wt % solvent, 10-25 wt % binder, and10-30 wt % pigment). Examples of suitable coating processes includegravure coating, sputtering, vacuum depositing, solution coating, or thelike. One or more layers (e.g., one to four layers) of the dispersionmay be applied to the substrate to yield coating 104, 104′, with coating104′ on a front side of dynamic window 102, coating 104 on a back sideof dynamic window 102, or both. In some cases, coating 104′ completelycovers the front side of dynamic window 102, coating 104 completelycovers the back side of dynamic window 102, or both. In other cases,portions of dynamic window 102 are free of coating 104, 104′, with theexcluded regions in the form of text, images, or the like. Coating 104,104′ is essentially free of solvent. A weight ratio of pigment to binderin coating 104, 104′ is typically in a range of 0.5 to 2 (e.g., a rangeof 0.75 to 1.75 or 1 to 1.5).

The inorganic pigment generally includes particles such as rod-shapedparticles or structured thin metallic platelets (e.g., flakes) that actas mirrors. The optical intensity of the platelets changes according tothe angle from which they are viewed. Maximum light intensity isachieved near the angle at which the incident light is totallyreflected. Minimum light intensity is experienced at an angle far awayfrom total reflection. After the dispersion is applied to the substrate,the solvent evaporates and the particles align on the substrate and areimmobilized in the binder, yielding aligned particles in a film on thesubstrate. When the primary light source is transmitted through thedynamic window toward the viewer, coating 104, 104′ has a transparentappearance.

Examples of suitable solvents include ketones, aliphatic or cyclicethers, and acetates, such as ethyl acetate, propyl acetate (e.g.,n-propyl acetate), butyl acetate (e.g., n-butyl acetate), and the like.Examples of suitable binders include PVCs, vinyl acetates, andcopolyester resins (e.g., VITEL copolyester resins available fromBostik, such as VITEL 2700B LMW and VITEL 5833B, and the like) that aresoluble in the solvent. Examples of suitable inorganic pigments includeIRIODIN/AFFLAIR 103 Rutile Sterling Silver (available from EMDChemicals) and FLAMENCO Gold 220C (available from BASF). IRIODIN/AFFLAIR103 Rutile Sterling Silver is a pearlescent silver pigment comprised ofmica-based flakes coated with a thin layer of metal oxides (e.g., TiO₂and SnO₂). FLAMENCO Gold 220C is a pearlescent gold pigment thatincludes mica and TiO₂. The interplay of colors produced by thesepigments is due to the layered structure of the metal oxides, which isalso imparts a rich, deep glossy effect. Particle sizes ranging fromabout 10 to about 60 microns are suitable for digital thermal printingribbon application described herein (e.g., 300 dpi). In one example,coating 104, 104′ is formed from a dispersion containing 12.4 wt %n-butyl acetate, 49.6 wt % n-propyl acetate, 16.5 wt % VITEL 2700B LMW,1.5 wt % VITEL 5833B, and 20 wt % Flamenco Gold 220C, such that theweight ratio of pigment to binder in coating 104, 104′ is about 1.

During personalization of the card blank, image 110 may be printed on atransparent layer (e.g., receiver layer 210) superimposed on dynamicwindow 102. Referring to ID document 100, when dynamic window 102 isviewed from back 108 of ID document 100 in reflected light, the lighttravels through transparent layers of the ID document and reflects fromcoating 104 imparting an opaque appearance to the dynamic window, andimage 110 is not visible. When dynamic window 102 is viewed from front106 of ID document 100 in reflected light, light travels throughtransparent layers of the ID document to image 110 and coating 104 andreflects from the coating, such that the image is seen to have abackground that corresponds to the coating. When dynamic window 102 isviewed from front 106 or back 108 of ID document 100 in transmittedlight (e.g. backlit), light is not reflected from coating 104 anddynamic window 102 has a transparent appearance, with image 110 visiblein the dynamic window. When an image is printed or superimposed on aback of dynamic window 102 (e.g., on receiver layer 210′), correspondingprinciples apply, based on the presence of coating 104, 104′, or both.

In one implementation, identical images are printed on each receiverlayer and on a front or back of the dynamic window, with the identicalimages superimposed such that the identical images appear to be a singleimage or three separate images based on the angle at which the dynamicwindow is viewed from the front of the identification document in lighttransmitted through the dynamic window from a back of the identificationdocument toward the front of the identification document.

In one example, a card blank corresponding to ID document 100 describedherein includes layers 202, 204, 204′, and 206, 206′, as defined below.

Structural layer 206: 6 or 7 mil polycarbonate (PC) (non-sensitized);

Tie layer 204: 5 mil five-layer co-extruded tie layer (e.g.,PETG/PETG+PC/PC/PETG+PC/PETG);

Core layer 202: 6 or 8 mil (depending upon the corresponding caliper ofthe structural layers to achieve ISO compliance) white polyvinylchloride (PVC) with window;

Tie layer 204′: 5 mil five-layer coextruded tie layer (e.g.,PETG/PETG+PC/PC/PETG+PC/PETG); and

Structural layer 206′: 6 or 7 mil PC (non-sensitized).

Receiver layers 210, 210′ (e.g., 2-6 mil D2T2 receiver layers) may becoated on structural layers 206, 206′, respectively, via a roll-basedgravure process in a separate coating unit as a part of the process ofpreparing the material components for assembly in a card structure. Theresulting card may be personalized in a CI or OTC setting and theprinted card may be overlaminated. In one example, overlamination layers212, 212′ may be applied over receiver layers 210, 210′, respectively,with a desktop (e.g., D2T2) printer or large in-line printer orlaminator (e.g., Datacard MX-6100).

It should be appreciated that while many of the Figures shown hereinillustrate a particular species of ID document—a driver license—thescope of this disclosure is not so limited. Rather, methods andtechniques described herein, apply generally to all ID documents definedabove. Moreover, techniques described herein are applicable to non-IDdocuments, e.g., such as printing or forming covert images on physicalobjects, holograms, etc., etc. Further, instead of ID documents, thetechniques described herein can be employed with product tags, productpackaging, business cards, bags, charts, maps, labels, etc., etc.,particularly those items including providing a non-visible indicia, suchas an image information on an over-laminate structure. The term IDdocument is broadly defined herein to include these tags, labels,packaging, cards, etc. In addition, while some of the examples above aredisclosed with specific core components, it is noted that laminates canbe sensitized for use with other core components. For example, it iscontemplated that aspects described herein may have applicability forarticles and devices such as compact disks, consumer products, knobs,keyboards, electronic components, decorative or ornamental articles,promotional items, currency, bank notes, checks, etc., or any othersuitable items or articles that may record information, images, and/orother data, which may be associated with a function and/or an object orother entity to be identified.

It should be appreciated that the methods described above with respectto FIGS. 1-6, as well as the methods for implementing and embeddingdigital watermarks, can be carried out on a general-purpose computer.These methods can, of course, be implemented using software, hardware,or a combination of hardware and software.

The technology and solutions disclosed herein have made use of elementsand techniques known from the cited documents. Other elements andtechniques from the cited documents can similarly be combined to yieldfurther implementations within the scope of the disclosure. Thus, forexample, single-bit watermarking can be substituted for multi-bitwatermarking, technology described as using imperceptible watermarks orencoding can alternatively be practiced using visible watermarks(glyphs, etc.) or other encoding, local scaling of watermark energy canbe provided to enhance watermark signal-to-noise ratio withoutincreasing human perceptibility, various filtering operations can beemployed to serve the functions explained in the prior art, watermarkscan include subliminal graticules to aid in image re-registration,encoding may proceed at the granularity of a single pixel (or DCTcoefficient), or may similarly treat adjoining groups of pixels (or DCTcoefficients), the encoding can be optimized to withstand expected formsof content corruption, etc. Thus, the exemplary embodiments are onlyselected samples of the solutions available by combining the teachingsreferenced above. The other solutions necessarily are not exhaustivelydescribed herein, but are fairly within the understanding of an artisangiven the foregoing disclosure and familiarity with the cited art. Theparticular combinations of elements and features in the above-detailedembodiments are exemplary only; the interchanging and substitution ofthese teachings with other teachings in this and theincorporated-by-reference patent documents are also expresslycontemplated.

Further modifications and alternative embodiments of various aspectswill be apparent to those skilled in the art in view of thisdescription. For example, while some of the detailed embodimentsdescribed herein use UV, IR, thermachromic, and optically variable inksand/or dyes by way of example, the present disclosure is not so limited.Accordingly, this description is to be construed as illustrative only.It is to be understood that the forms shown and described herein are tobe taken as examples of embodiments. Elements and materials may besubstituted for those illustrated and described herein, parts andprocesses may be reversed, and certain features may be utilizedindependently, all as would be apparent to one skilled in the art afterhaving the benefit of this description.

What is claimed is:
 1. An identification document comprising: amultilayer laminate comprising a core layer defining an openingtherethrough; and a dynamic window in the opening, the dynamic windowcomprising an optically variable coating on a back of the dynamicwindow, wherein a front of the dynamic window is between a front of theidentification document and the back of the dynamic window, the back ofthe dynamic window is between a back of the identification document andthe front of the dynamic window; and an image superimposed on the frontof the dynamic window, wherein the image is visible and the entiredynamic window provides a transparent background for the image when theimage is viewed from the front of the identification document in lighttransmitted through the dynamic window from the back of theidentification document toward the front of the identification document,and the image is visible and the entire dynamic window provides anontransparent background for the image when the image is viewed fromthe front of the identification document in light reflected from thefront of the identification document.
 2. The identification document ofclaim 1, wherein the optically variable coating comprises an inorganicpigment dispersed in a binder, and the inorganic pigment comprisesparticles aligned in the binder to yield a mirror effect in reflectedlight.
 3. The identification document of claim 1, wherein an opticalintensity of the dynamic window changes according to an angle at whichthe dynamic window is viewed in reflected light.
 4. The identificationdocument of claim 3, wherein a maximum optical intensity of the dynamicwindow in reflected light is achieved near an angle at which incidentlight is totally reflected from the optically variable coating.
 5. Theidentification document of claim 4, wherein the dynamic window appearsto be opaque when the incident light is totally reflected from theoptically variable coating.
 6. The identification document of claim 1,wherein the image is printed on a layer of the multilayer laminatebetween the front of the identification document and the front of thedynamic window.
 7. The identification document of claim 6, wherein theimage is a color image.
 8. The identification document of claim 6,wherein the image is visible from the front of the identificationdocument in light reflected from the front of the identificationdocument and is visible from the front of the identification document inlight transmitted from the back of the identification document throughthe dynamic window.
 9. The identification document of claim 6, whereinthe image is invisible from the back of the identification document inlight reflected from the back of the identification document and isvisible from the back of the identification document in lighttransmitted from the front of the identification document through thedynamic window.
 10. The identification document of claim 1, wherein thedynamic window is laser engraved, and the laser engraving is visiblewhen the identification document is viewed from the front with lighttransmitted from the back of the identification document to the front ofthe identification document through the dynamic window, and the laserengraving is not visible when the identification document is viewed fromthe front of the identification document in reflected light.
 11. Theidentification document of claim 1, wherein the multilayer laminate isdevoid of an adhesive composition.
 12. The identification document ofclaim 1, comprising a tie layer laminated to each side of the corelayer, wherein each tie layer comprises multiple layers of chemicallymodified resins.
 13. The identification document of claim 12, comprisinga structural layer laminated to an outer side of each tie layer.
 14. Theidentification document of claim 13, comprising a receiver layeradjacent an outer side of each structural layer.
 15. The identificationdocument of claim 14, wherein images identical to the image superimposedon the front of the dynamic window are printed on each receiver layer,wherein the identical images are superimposed such that the identicalimages appear to be a single image or three separate images based on anangle at which the dynamic window is viewed from the front of theidentification document in light transmitted through the dynamic windowfrom the back of the identification document toward the front of theidentification document.
 16. The identification document of claim 12,comprising a laser engraved image formed in at least one of the tielayers.
 17. The identification document of claim 16, wherein the laserengraved image is a hologram.
 18. The identification document of claim16, wherein the optically variable coating is not altered by the laserengraved image.
 19. The identification document of claim 1, wherein thedynamic window comprises a clear plastic layer.
 20. The identificationdocument of claim 1, wherein the optically variable coating is a firstoptically variable coating, and further comprising a second opticallyvariable coating on the front of the dynamic window.
 21. Theidentification document of claim 20, wherein the first opticallyvariable coating is different from the second optically variablecoating.
 22. The identification document of claim 1, wherein theoptically variable coating completely covers the back of the dynamicwindow.
 23. The identification document of claim 1, wherein theoptically variable coating covers selected portions of the back of thedynamic window.
 24. The identification document of claim 1, wherein theoptically variable coating comprises at least one of an opticallyvariable pigment, an optically variable ink, an optically variable dye,and an optically variable colorant.
 25. A method of fabricating anidentification document, the method comprising: forming an opening in acore layer; positioning a dynamic window in the opening, the dynamicwindow comprising an optically variable coating on a back of the dynamicwindow, wherein the front of the dynamic window is between a front ofthe identification document and the back of the dynamic window, the backof the dynamic window is between a back of the identification documentand the front of the dynamic window; and superimposing an image on thefront of the dynamic window, wherein the image is visible and the entiredynamic window provides a transparent background for the image when theimage is viewed from the front of the identification document in lighttransmitted through the dynamic window from the back of theidentification document toward the front of the identification document,and the image is visible and the entire dynamic window provides anontransparent background for the image when the image is viewed fromthe front of the identification document in light reflected from thefront of the identification document; and plate laminating the corelayer and the dynamic window between at least one outer layer on eachside of the core layer.
 26. The method of claim 25, wherein thelaminating occurs in the absence of an adhesive composition.